English▸ noun a very thin, light, crisp, sweet cookie or cracker, especially one of a kind eaten with ice cream.
▪ a thin disk of unleavened bread used in the Eucharist.
▪ Electronics a very thin slice of a semiconductor crystal used as the substrate for solid-state circuitry.
▪ historical a small disk of dried paste formerly used for fastening letters or holding papers together.
▪ a round, thin piece of something:
a wafer of ice.
▸ verb [with object] archaic fasten or seal (a letter or document) with a wafer.